I had 2 level TLIF 4/18. I am a side sleeper. I would turn in different directions inch by once until I fit d the least painful position. I had no problem sleeping on my back post surgery. I have started sleeping in my side again with a pillow between my legs as instructed by pt. Like the previous response, you will just know not to bend or twist. Btw has my follow up yesterday and all is great and I feel great!